This invention relates to a process for manufacturing an edible, simulated meat product, and more particularly, to a process for manufacturing a meat-like lump, sheet or block of protein fibers.
Conventionally, many process methods for manufacturing an edible, metal-like food material through processing edible protein source materials have been proposed.
Although a wet spinning method, in which a protein-containing alkaline dope prepared from highly purified protein is forced through a spinneret into an acid coagulating bath for coagulation thereof, may be typical, the resultant independent fibers hardly provide a specific meat-like sensation to the mouth. Therefore, the fibers thus processed are generally further introduced into a drawing or stretching step and then into an immersing step with binders such as albumin or the like so that the resultant fibers are arranged to be layered as tows of fibers.
However, owing to the necessity for the preparation of the highly purified protein as well as problems associated with the waste liquid treatments resulting from the broad pH range involved, the known wet spinning method is usually expensive to operate.
According to another typical method for manufacturing the protein fibers, a protein slurry adjusted for pH is simultaneously forced to flow and is heated by means of a heat exchanger of the tubular type or ejector to allow the substance to be formed in an apparently fibrous coagulation. However, the resultant protein fibers obtained by the method as described above and showing a fibril structure (i.e., branched structure) cannot be towed at all due to the specific randomly oriented and noncontinuous, structural characteristics thereof.
For the formation of the meat-like protein fibers as described above (including those in the form of tows) into a meat-like lump or block, it has been a general practice to mix such protein fibers with a binding material so as to be molded for subsequent heating and solidification, with the process for the fiber formation being completely separate from the process for lump or block formation. The processes for fabricating the meat-like sheet or block of protein fibers from the edible protein source materials, comprises a first step for processing protein fibers, and a successive step for fabricating these protein fibers into the sheet or block form as described above, in which the two steps are independently necessary and must be performed in succession.
A protein fiber fabrication process disclosed, for example, in U.S. Pat. No. 3,794,731 (Patented Feb. 26, 1974) comprises a procedure of forcing an aqueous alkaline protein solution through an orifice and simultaneously intimately containing the protein stream with a stream of a fast acting acid gas in an amount sufficient to coagulate the protein and form the protein fibers with said gas travelling at a velocity greater than the protein stream. Additionally, the prior art mentioned above further indicates a possibility of constructing a composite mat of protein fibers in one operation, wherein the fibers can be formed while separate sources of other materials, such as binders, flavors etc. are also sprayed onto the receiving surface. The composite mat can then be removed from the receiving surface to yield the final product in one operation.
The process of the prior art mentioned above still requires a broad pH range, in which the purified starting protein, which is first rendered alkaline, should be successively acidified to coagulate and form fibers from the solution mentioned above, although the mat of protein fibers is conceivably constructed in one operation.
The present inventors have obtained, in the course of their research, experimental evidence which makes it possible to construct a novel fabricating process to improve the prior art process as described above, with special reference to the specific phenomenon related to the coagulation which is brought about within the short lapse of time immediately after the pH adjusted protein slurry having just completed the simultaneous flowing and heating procedure as described in the foregoing.
Specifically, as will be detailed hereinbelow, the novel manufacturing process of the present invention permits the two steps mentioned above to be accomplished in one operation and yet, the resultant sheet-like or block-like formation of the meat-like protein fibers of a condensed structural characteristics are advantageously obtained.